The present invention affords a highly efficacious method for the prevention and treatment of infections wherein the causative organism is Sphaerophorus necrophorus, an anaerobic, gram negative bacillus. This organism has been demonstrated to be the causative agent of foot rot in cattle, sheep and goats, liver abscesses and calf diphtheria in cattle, necrotic pneumonia in swine, and necrotic rhinitis in sheep, cattle and swine, diseases which are economically damaging to the commercial raisers of these animals.
Ipronidazole is a known compound which chemically is 1-methyl-2-isopropyl-5-nitroimidazole. The preparation of this compound and its pharmaceutically acceptable acid addition salts are described in U.S. Pat. No. 3,634,446 which issued Jan. 11, 1972. In said patent, the compound is disclosed as possessing antiprotozoal and antihistomonal activity, particularly the latter. The compound is described as being especially active in the treatment of the histomonal infection known as turkey blackhead disease or enterohepatitis. Ipronidazole, however, is not recognized in the art as possessing antibacterial activity. Such activity cannot be imputed from U.S. Pat. No. 3,737,546 issued June 5, 1973, which teaches the use of ipronidazole in the prevention and treatment of swine dysentery wherein the causative organism is the large spirochete Treponema hyodysenteriae. Another patent, Japanese Pat. No. 7305024, describes mouthwash compositions containing as the active ingredient metronidazole, which is chemically related to ipronidazole and which chemically is 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole. Such compositions are described as possessing strong activity against oral anaerobes such as Peptococcus, Veillonella, Bacteriodes, Fusobacterium ad Treponema. The disclosure of the use of this compound locally as a mouthwash is not viewed as suggesting that ipronidazole would be highly efficacious systemically against S. necrophorus infections. A recent paper has suggested, on the basis of in vitro studies and very limited clinical work that metronidazole may be of value in treating infections wherein the causative organisms are obligately anaerobic bacteria. These limited disclosures are not viewed as suggesting that the active ingredient of the present invention is highly efficacious in the treatment of infections wherein the causative organism is Sphaerophorus necrophorus.